Patent GB-843541-A (GB)
Title: Improved light-sensitive polymers for photomechanical printing processes
IPC: C08F20/34
Filed: 1956-07-30
Abstract: Film-forming organic polymeric material containing a substantial proportion of side chains which have -N3 groups attached to carbon atoms therein, there being not more than two -N3 groups attached to any side chain, may be prepared (1) by diazotising and reacting with sodium azide an aminostyrene polymer, which may be prepared by nitrating and reducing a styrene polymer, (2) by condensing hydroxylic polymers, e.g. partially hydrolysed vinyl or isopropenyl ester polymers, starch, guar, alginic acid, or cellulose or its partial ethers or esters, with azido acid chlorides, azido acid anhydrides or azido aldehydes, (3) by reacting amino group containing polymers, e.g. polyvinylamines, polyvinyl anthranilates and polymeric aminotriazoles, with azido acid chlorides or anhydrides, (4) by reacting carboxyl containing polymers with azido alcohols and (5) by reacting polyvinyl halogen-substituted esters, e.g. polyvinyl chloracetate, a -chlorpropionate or o -chlorbutyrate, with sodium azide.  Many suitable reactants are listed and examples describe diazotising and reacting with sodium azide (1) poly-p-aminostyrne and (2) p-aminostyrene-maleic acid copolymer; (3) condensing p-azidobenzoyl chloride with partially hydrolysed poly-vinyl acetate; condensing 3-azidophthalic anhydride with (4) partially hydrolysed polyvinyl acetate and (6) partially hydrolysed cellulose acetate; condensing 3 (4)-azido-phthalic anhydride (mixed isomers) with (5) partially hydrolysed polyvinyl acetate and (8) ethylene-vinyl alcohol copolymer; esterifying styrene-maleic anhydride copolymers with (9) b -(4-azidophenoxy) ethanol and (10) m-azidobenzyl alcohol; and (11) reacting polyvinyl chloracetate with sodium azide.  The polymeric materials may be coated from solutions e.g. in aqueous ammonium hydroxide with or without a small amount of ethanol acetone, dioxane, methyl ethyl ketone of dimethylformamide, on printing plate supports, e.g. of aluminium, zinc, copper, magnesium and alloys, and, after exposure to ultra-violet light through a negative, resist images may be developed by treatment with dilute aqueous alkali.  The polymers may be sensitised with 2-benzoyl-methylene-1-methyl-b -naphthothazoline.  Specifications 843,542 and 843,543 are referred toALSO:Film forming organic polymeric materials containing a substantial proportion of side chains which have -N3 groups attached to carbon atoms therein, there being not more than two -N3 groups, may be prepared by reacting azidoacid chlorides, e.g. azido benzoyl chloride, or azido acid anhydrides, e.g. azido phthalic anhydride, with proteins, e.g. gelatin and casein.  In Example 7 gelatin, dissolved in water, is reacted with 3-azidophthalic anhydride in the presence of sodium hydroxide. The polymeric materials may be coated from solution on to printing plate supports and used in photomechanical printing processes.  p-Azidobenzoyl chloride may be prepared by diazotising p-aminobenzoic acid and reacting with sodium azide to give p-azidobenzoic acid, and reacting the latter with thionyl chloride.  b -(4-azidophenoxy) ethanol may be prepared by reacting sodium p-nitrophenate and ethylene chlorohydrin, hydrogenating in the presence of platinum oxide, diazotising the b -(4-aminophenoxy)ethanol formed and reacting with sodium azide. m-Azidobenzyl alcohol may be prepared by hydrogenating m-nitrobenzyl alcohol, diazotising and reacting with sodium azide. m-Azidobenzaldehyde may be prepared by diazotising m-aminobenzaldehyde and reacting with sodium azide.  3-Azidophthalic anhydride may be prepared by reducing 3-nitrophthalic acid with stannous chloride, diazotising and reacting with sodium azide to give 3-azidophthalic acid, and heating the latter with acetic anhydride. Specifications 843,542 and 843,543 are referred to.